/Engine/Source/Runtime/Slate/Public/Widgets/Text/SlateTextBlockLayout.h
Get the computed desired size for this layout, updating the internal cache as required
FVector2D ComputeDesiredSize ( const [FWidgetDesiredSizeArgs](API\Runtime\Slate\Widgets\Text\FSlateTextBlockLayout\FWidgetDesiredSizeArgs) & InWidgetArgs, const float InScale )